Study on preferential flow in dump leaching of low-grade ores

Wu, Aixiang; Yin, Shenghua; Yang, Baohua; Wang, Jun; Qiu, Guanzhou

doi:10.1016/j.hydromet.2007.03.001

Cited by 60 publications

(23 citation statements)

References 6 publications

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“…This, coupled with the highly inhomogeneous structure of the ore beds which is another feature of the wide particle size distribution, means that existing models of hydrodynamics in similar well-described chemical systems, such as trickle bed reactors, do not adequately describe the heaps. Most heap bioleaching hydrology studies have considered the use of tracers to extract hydrodynamic parameters and develop models of the liquid flow (Bouffard and Dixon, 2001;De Andrade Lima, 2006) or to study the issue of preferential flow resulting from the inhomogeneous heap structure (Decker and Tyler, 1999;O'Kane Consultants Inc., 2000;Wu et al, 2007) for which analogies to unsaturated soil hydrodynamics have proved particularly successful. However, the liquid distribution within a heap from a drip irrigation point, one of the most common methods of irrigation (Bartlett, 1998;Kappes, 2002), has not been examined in any specific detail.…”

Section: Introductionmentioning

confidence: 99%

MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching micro-organisms

et al. 2014

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Heap bioleaching performance is dependent on the contacting of the leach solution with the ore bed, hence on the system hydrodynamics. In this study two experimental setups were used to examine hydrodynamics associated with irrigation from a single drip emitter, one of the most common methods of heap irrigation. A specialist magnetic resonance imaging (MRI) method which is insensitive to the metal content of the ore was used to examine the liquid flow into an ore bed in the immediate vicinity of an irrigation point. The distribution of liquid in, microbial colonisation of and mineral recovery from a bioleach of a large scale 132 kg "ore slice" were subsequently monitored using sample ports positioned along the breadth and height of the reactor. In both systems the lateral movement of the liquid increased with bed depth, though preferential flow was evident. The majority of the liquid flow was in the region directly below the irrigation point and almost no liquid exchange occurred in the areas of lowest liquid content at the upper corners of the bed in which fluid exchange was driven by capillary action. The MRI studies revealed that the liquid distribution was unchanging following an initial settling of the ore bed and that, at steady state, the majority (~60%) of the liquid flowed directly into established large channels. The limited lateral movement of the liquid had a significant impact on the local leaching efficiencies and microbial colonisation of the ore with cell concentrations in the regions of lowest liquid content lying below the detection limit. Hence poor lateral liquid distribution with drip irrigation, and the associated impact on colonisation was identified as a significant disadvantage of this irrigation approach. Further, the need to optimise fluid exchange throughout the ore bed was identified as key for optimisation of leaching performance.

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Section: Introductionmentioning

confidence: 99%

MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching micro-organisms

et al. 2014

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“…Waste rock can be an extremely heterogeneous material with grain size ranging from small soil particles to large boulders with diameters of a few meters [24]. The grain size distribution of the treated and untreated samples is presented in Figs. 10 and 11.…”

Section: Particle Sizementioning

confidence: 99%

Effects of bioleaching on the mechanical and chemical properties of waste rocks

Yin

Wang

et al. 2012

Int J Miner Metall Mater

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Bioleaching processes cause dramatic changes in the mechanical and chemical properties of waste rocks, and play an important role in metal recovery and dump stability. This study focused on the characteristics of waste rocks subjected to bioleaching. A series of experiments were conducted to investigate the evolution of rock properties during the bioleaching process. Mechanical behaviors of the leached waste rocks, such as failure patterns, normal stress, shear strength, and cohesion were determined through mechanical tests. The results of SEM imaging show considerable differences in the surface morphology of leached rocks located at different parts of the dump. The mineralogical content of the leached rocks reflects the extent of dissolution and precipitation during bioleaching. The dump porosity and rock size change under the effect of dissolution, precipitation, and clay transportation. The particle size of the leached rocks decreased due to the loss of rock integrity and the conversion of dry precipitation into fine particles.

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“…In addition to their ability to degrade organic matter and reduce sulfate, the ability of SRB to precipitate many heavy metals present in wastewater has also been extensively researched. Studies have reported zinc precipitation by a mixture culture of SRB [46], and SRB-mediated bioremediation of chrome [47], iron [48], zinc and copper [49][50][51][52] has also been studied.…”

Section: Characterization Of Strain H1mentioning

confidence: 99%